1. Field of the Invention
The present invention relates to a new and distinct variety or cultivar of the ornamental shrub, Vitex negundo, commonly known simply as vitex or vernacular names such as chaste tree, spice lilac, spice tree, monks pepper-tree, wild pepper, Indian spice, hemp-tree, sage-tree, wild lavender, tree of chastity.
2. Description of the Related Art
Vitex negundo is native to a broad area of China and SE Asia and has naturalized over a much wider area of the middle East and Africa. One hypothesis is that Chinese traders preparing to travel the silk road, would pack seeds and leaves of Vitex in among goods to prevent damage from insects and rodents. Along the route, seeds of Vitex would be inadvertently dispersed. It seems likely that Vitex agnus-castus, considered to be native to the middle East and parts of southern Europe and northern Africa, derived from ancestral Chinese Vitex negundo seeds centuries ago. It was introduced into cultivation in North America about 1600.
Vitex flowers on new growth and produce large quantities of seeds. Seedlings of Vitex negundo have become so invasive in some areas so as to be considered a weed. The plant constantly emits a pleasant and distinct spice-like odor during the growing season. Brush a twig or a few leaves and release of the volatile oil increases. The volatile oil acts as a deterrent to most insects, for example, grasshoppers are commonly seen hiding among leaves, yet feeding does not occur. Even when dormant, the odor remain sufficient to prevent rodent damage and deer from feeding on branches or rubbing on large stems.
In the USA, an assortment of seedlings have been selected, given varietal names and introduced into the nursery trade. Criteria for selection have been flower color, size of panicles and other growth features. However, to date, use in landscapes has been limited because all become large plants that produce lots of troublesome seeds. To date, no vitex cultivars have been patented.
The new dwarf and sterile variety of vitex claimed herein, which has been given the cultivar name ‘WHIT L’ is a seedling selected from a block of about 8,000 seedlings which were 11 generational descendants from the original parent used to begin this research in 1986. The plant is from this breeding program that began in 1986, in which the parent was selected based on many features that were desirable, but not exceptional. The seeds from the parent are extremely variable, with wide ranging features. The plant ‘WHIT L’ was the only seedling saved from approximately 450 seedling from the parent.
This new and distinct vitex was asexually reproduced by rooting softwood cuttings taken from the original ‘WHIT L’ plant near Stillwater, Okla. The asexually reproduced plants show all of the unique features that characterize of this vitex. As a further test, cuttings were taken from the asexually propagated plants. These secondary cuttings rooted and grew the same as the parent, indicating that the unique features of this plant are stable through successive generations of asexual reproduction.